Is the design of the playing cards open? I am always looking for nice demos for our open source database publishing software, which does handle cmyk + spotcolors etc. (https://speedata.github.io/publisher/index.html)
Sort of. Still busy with work and other things, but eventually it should all be available somewhere. Drop me a mail and I can give you a link. And your application looks like a very close fit of what I actually was looking for when I began this.